<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * Common Functions
 *
 * Loads the base classes and executes the request.
 *
 * @package		CodeIgniter
 * @subpackage	codeigniter
 * @category	Common Functions
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/
 */

// ------------------------------------------------------------------------

/**
 * Determines if the current version of PHP is greater then the supplied value
 *
 * Since there are a few places where we conditionally test for PHP > 5
 * we'll set a static variable.
 *
 * @access	public
 * @param	string
 * @return	bool	TRUE if the current version is $version or higher
 */
function is_php($version = '5.0.0')
{
	static $_is_php;
	$version = (string)$version;

	if ( ! isset($_is_php[$version]))
	{
		$_is_php[$version] = (version_compare(PHP_VERSION, $version) < 0) ? FALSE : TRUE;
	}

	return $_is_php[$version];
}

// ------------------------------------------------------------------------

/**
 * Tests for file writability
 *
 * is_writable() returns TRUE on Windows servers when you really can't write to
 * the file, based on the read-only attribute.  is_writable() is also unreliable
 * on Unix servers if safe_mode is on.
 *
 * @access	private
 * @return	void
 */
function is_really_writable($file)
{
	// If we're on a Unix server with safe_mode off we call is_writable
	if (DIRECTORY_SEPARATOR == '/' AND @ini_get("safe_mode") == FALSE)
	{
		return is_writable($file);
	}

	// For windows servers and safe_mode "on" installations we'll actually
	// write a file then read it.  Bah...
	if (is_dir($file))
	{
		$file = rtrim($file, '/').'/'.md5(mt_rand(1,100).mt_rand(1,100));

		if (($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
		{
			return FALSE;
		}

		fclose($fp);
		@chmod($file, DIR_WRITE_MODE);
		@unlink($file);
		return TRUE;
	}
	elseif (($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE)
	{
		return FALSE;
	}

	fclose($fp);
	return TRUE;
}

// ------------------------------------------------------------------------

/**
 * Class registry
 *
 * This function acts as a singleton.  If the requested class does not
 * exist it is instantiated and set to a static variable.  If it has
 * previously been instantiated the variable is returned.
 *
 * @access	public
 * @param	string	the class name being requested
 * @param	string	the directory where the class should be found
 * @param	string	the class name prefix
 * @return	object
 */
function &load_class($class, $directory = 'libraries', $prefix = 'CI_')
{
	static $_classes = array();

	// Does the class exist?  If so, we're done...
	if (isset($_classes[$class]))
	{
		return $_classes[$class];
	}

	$name = FALSE;

	// Look for the class first in the native system/libraries folder
	// thenin the local application/libraries folder
	foreach (array(BASEPATH, APPPATH) as $path)
	{
		if (file_exists($path.$directory.'/'.$class.EXT))
		{
			$name = $prefix.$class;

			if (class_exists($name) === FALSE)
			{
				require($path.$directory.'/'.$class.EXT);
			}

			break;
		}
	}

	// Is the request a class extension?  If so we load it too
	if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.EXT))
	{
		$name = config_item('subclass_prefix').$class;

		if (class_exists($name) === FALSE)
		{
			require(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.EXT);
		}
	}

	// Did we find the class?
	if ($name === FALSE)
	{
		// Note: We use exit() rather then show_error() in order to avoid a
		// self-referencing loop with the Excptions class
		exit('Unable to locate the specified class: '.$class.EXT);
	}

	// Keep track of what we just loaded
	is_loaded($class);

	$_classes[$class] = new $name();
	return $_classes[$class];
}

// --------------------------------------------------------------------

/**
 * Keeps track of which libraries have been loaded.  This function is
 * called by the load_class() function above
 *
 * @access	public
 * @return	array
 */
function is_loaded($class = '')
{
	static $_is_loaded = array();

	if ($class != '')
	{
		$_is_loaded[strtolower($class)] = $class;
	}

	return $_is_loaded;
}

// ------------------------------------------------------------------------

/**
 * Loads the main config.php file
 *
 * This function lets us grab the config file even if the Config class
 * hasn't been instantiated yet
 *
 * @access	private
 * @return	array
 */
function &get_config($replace = array())
{
	static $_config;

	if (isset($_config))
	{
		return $_config[0];
	}

	// Fetch the config file
	if ( ! file_exists(APPPATH.'config/config'.EXT))
	{
		exit('The configuration file does not exist.');
	}
	else
	{
		require(APPPATH.'config/config'.EXT);
	}

	// Does the $config array exist in the file?
	if ( ! isset($config) OR ! is_array($config))
	{
		exit('Your config file does not appear to be formatted correctly.');
	}

	// Are any values being dynamically replaced?
	if (count($replace) > 0)
	{
		foreach ($replace as $key => $val)
		{
			if (isset($config[$key]))
			{
				$config[$key] = $val;
			}
		}
	}

	return $_config[0] =& $config;
}

// ------------------------------------------------------------------------

/**
 * Returns the specified config item
 *
 * @access	public
 * @return	mixed
 */
function config_item($item)
{
	static $_config_item = array();

	if ( ! isset($_config_item[$item]))
	{
		$config =& get_config();

		if ( ! isset($config[$item]))
		{
			return FALSE;
		}
		$_config_item[$item] = $config[$item];
	}

	return $_config_item[$item];
}

// ------------------------------------------------------------------------

/**
 * Error Handler
 *
 * This function lets us invoke the exception class and
 * display errors using the standard error template located
 * in application/errors/errors.php
 * This function will send the error page directly to the
 * browser and exit.
 *
 * @access	public
 * @return	void
 */
function show_error($message, $status_code = 500, $heading = 'An Error Was Encountered')
{
	$_error =& load_class('Exceptions', 'core');
	echo $_error->show_error($heading, $message, 'error_general', $status_code);
	exit;
}

// ------------------------------------------------------------------------

/**
 * 404 Page Handler
 *
 * This function is similar to the show_error() function above
 * However, instead of the standard error template it displays
 * 404 errors.
 *
 * @access	public
 * @return	void
 */
function show_404($page = '', $log_error = TRUE)
{
	$_error =& load_class('Exceptions', 'core');
	$_error->show_404($page, $log_error);
	exit;
}

// ------------------------------------------------------------------------

/**
 * Error Logging Interface
 *
 * We use this as a simple mechanism to access the logging
 * class and send messages to be logged.
 *
 * @access	public
 * @return	void
 */
function log_message($level = 'error', $message, $php_error = FALSE)
{
	static $_log;

	if (config_item('log_threshold') == 0)
	{
		return;
	}

	$_log =& load_class('Log');
	$_log->write_log($level, $message, $php_error);
}

// ------------------------------------------------------------------------

/**
 * Set HTTP Status Header
 *
 * @access	public
 * @param	int		the status code
 * @param	string
 * @return	void
 */
function set_status_header($code = 200, $text = '')
{
	$stati = array(
	200	=> 'OK',
	201	=> 'Created',
	202	=> 'Accepted',
	203	=> 'Non-Authoritative Information',
	204	=> 'No Content',
	205	=> 'Reset Content',
	206	=> 'Partial Content',

	300	=> 'Multiple Choices',
	301	=> 'Moved Permanently',
	302	=> 'Found',
	304	=> 'Not Modified',
	305	=> 'Use Proxy',
	307	=> 'Temporary Redirect',

	400	=> 'Bad Request',
	401	=> 'Unauthorized',
	403	=> 'Forbidden',
	404	=> 'Not Found',
	405	=> 'Method Not Allowed',
	406	=> 'Not Acceptable',
	407	=> 'Proxy Authentication Required',
	408	=> 'Request Timeout',
	409	=> 'Conflict',
	410	=> 'Gone',
	411	=> 'Length Required',
	412	=> 'Precondition Failed',
	413	=> 'Request Entity Too Large',
	414	=> 'Request-URI Too Long',
	415	=> 'Unsupported Media Type',
	416	=> 'Requested Range Not Satisfiable',
	417	=> 'Expectation Failed',

	500	=> 'Internal Server Error',
	501	=> 'Not Implemented',
	502	=> 'Bad Gateway',
	503	=> 'Service Unavailable',
	504	=> 'Gateway Timeout',
	505	=> 'HTTP Version Not Supported'
	);

	if ($code == '' OR ! is_numeric($code))
	{
		show_error('Status codes must be numeric', 500);
	}

	if (isset($stati[$code]) AND $text == '')
	{
		$text = $stati[$code];
	}

	if ($text == '')
	{
		show_error('No status text available.  Please check your status code number or supply your own message text.', 500);
	}

	$server_protocol = (isset($_SERVER['SERVER_PROTOCOL'])) ? $_SERVER['SERVER_PROTOCOL'] : FALSE;

	if (substr(php_sapi_name(), 0, 3) == 'cgi')
	{
		header("Status: {$code} {$text}", TRUE);
	}
	elseif ($server_protocol == 'HTTP/1.1' OR $server_protocol == 'HTTP/1.0')
	{
		header($server_protocol." {$code} {$text}", TRUE, $code);
	}
	else
	{
		header("HTTP/1.1 {$code} {$text}", TRUE, $code);
	}
}

// --------------------------------------------------------------------

/**
 * Exception Handler
 *
 * This is the custom exception handler that is declaired at the top
 * of Codeigniter.php.  The main reason we use this is to permit
 * PHP errors to be logged in our own log files since the user may
 * not have access to server logs. Since this function
 * effectively intercepts PHP errors, however, we also need
 * to display errors based on the current error_reporting level.
 * We do that with the use of a PHP error template.
 *
 * @access	private
 * @return	void
 */
function _exception_handler($severity, $message, $filepath, $line)
{
	// We don't bother with "strict" notices since they tend to fill up
	// the log file with excess information that isn't normally very helpful.
	// For example, if you are running PHP 5 and you use version 4 style
	// class functions (without prefixes like "public", "private", etc.)
	// you'll get notices telling you that these have been deprecated.
	if ($severity == E_STRICT)
	{
		return;
	}

	$_error =& load_class('Exceptions', 'core');

	// Should we display the error? We'll get the current error_reporting
	// level and add its bits with the severity bits to find out.
	if (($severity & error_reporting()) == $severity)
	{
		$_error->show_php_error($severity, $message, $filepath, $line);
	}

	// Should we log the error?  No?  We're done...
	if (config_item('log_threshold') == 0)
	{
		return;
	}

	$_error->log_exception($severity, $message, $filepath, $line);
}

// --------------------------------------------------------------------

/**
 * Remove Invisible Characters
 *
 * This prevents sandwiching null characters
 * between ascii characters, like Java\0script.
 *
 * @access	public
 * @param	string
 * @return	string
 */
function remove_invisible_characters($str)
{
	static $non_displayables;

	if ( ! isset($non_displayables))
	{
		// every control character except newline (dec 10), carriage return (dec 13), and horizontal tab (dec 09),
		$non_displayables = array(
										'/%0[0-8bcef]/',			// url encoded 00-08, 11, 12, 14, 15
										'/%1[0-9a-f]/',				// url encoded 16-31
										'/[\x00-\x08]/',			// 00-08
										'/\x0b/', '/\x0c/',			// 11, 12
										'/[\x0e-\x1f]/'				// 14-31
		);
	}

	do
	{
		$cleaned = $str;
		$str = preg_replace($non_displayables, '', $str);
	}
	while ($cleaned != $str);

	return $str;
}


/* End of file Common.php */
/* Location: ./system/core/Common.php */